For specific keyword, our client’s site appears, disappears, appears and disappears from the Google first page often. It’s currently on page 2 of Yahoo/Bing. It was on the Google PR1 for 3 days and it disappeared again and I am sure if we resubmit it again, it’ll show up sooner or later for a few days.
Online and offline optimization has been completed.
The site owners believe that the problems rest elsewhere. It cannot be the Google's Panda as it stays on the first page for a long time and then it disappears and reappears again.
What is the problem, if you can detect the problem and fix it, we’ll award you the job. Additional information will be provided via PM. Please start your response with “We may have an idea”.